Circuit board and a method for making the same

ABSTRACT

A method for making a multi-layer electronic circuit board  136  having electroplated apertures  96, 98  which may be selectively and electrically isolated from an electrically grounded member  46  and further having selectively formed air bridges and/or crossover members  128  which are structurally supported by material  134.

This application claims benefit of Provisional No. 60/207,647 filed May26, 2000.

FIELD OF THE INVENTION

The present invention relates to an electronic circuit board and amethod for making an electronic circuit board and more particularly, toa multi-layer electronic circuit board having metallized apertures whichare selectively isolated and/or disconnected from an electrical groundplane and further having selectively formed air bridges and/or crossovercircuits.

BACKGROUND OF THE INVENTION

Multi-layer circuit boards operatively receive electronic components andallow the received components to be desirably interconnected and toselectively and cooperatively form electrical circuits. Particularly,these components are operatively received upon opposed board surfacesand within certain interior portions of the board, thereby desirablyallowing each of the electronic circuit boards to contain a relativelylarge amount of components which efficiently, respectively, and denselypopulate the respective boards.

It is desirable to allow each of the component containing surfaces orportions of a created and/or formed electronic circuit board tocommunicate and/or be selectively interconnected, thereby allowing thecontained electronic components to cooperatively and selectively form arelatively large number of desired electrical circuits. This desiredcommunication and/or interconnection typically requires the use ofshared electrical ground planes, the transmittal of electrical powerand/or control type signals between some or all of the componentcontaining surfaces or board portions, and/or the connection ofcomponents on each of the opposed surfaces and/or within and betweencertain of the interior portions and the top and/or bottom and/or otherboard surfaces.

This desired interconnection typically requires that one or more holesbe formed or drilled through each of the circuit boards, therebycreating at least one “through hole” or “via” traversing between each ofthe opposed component containing surfaces and through the variousinterior circuit board portions. Typically this drilling process isrelatively complex and time consuming, thereby increasing the overallcircuit board production cost. This drilling process also undesirablydamages and/or destroys many of the circuit boards, thereby furtherincreasing overall production costs.

Further, it is desirable to form “air-bridges” or “crossover typecircuits” upon one or more selected surfaces and/or within certaincomponent containing portions of the formed circuit board in order toallow multiple levels of circuits and/or electrical interconnections tobe formed upon a single board surface and/or within a certain componentcontaining portion of the circuit board, thereby desirably increasingthe amount of electrical circuits which may be created upon and/orwithin the created circuit board (e.g., increasing the density of thecontained electrical circuitry).

These “air-bridges” or crossover circuits are typically formed by rathercomplicated, costly, and time consuming processes. The formed bridgesand crossover circuits further do not typically and efficientlyaccommodate certain desirable circuit board interconnection processes,techniques, and/or methodologies such as and without limitation, the useof relatively heavy wire bonding (e.g., aluminum wire having a diameterof about five to about twenty millimeters) or the direct connection ofcomponents to a surface of the board.

There is therefore a need to provide an electronic circuit board and amethod for producing a multi-layer electronic circuit board whichovercomes some or all of the previously delineated drawbacks of priorelectronic circuit boards and methods for making a circuit board, whichselectively allows grounded and non-grounded “vias” to be desirably andselectively and efficiently formed in a cost effective manner, and whichfurther allows for the efficient and selective formation of air-bridgemembers or crossover circuits which desirably accommodate diverse typesof circuit interconnection processes, and which increase the circuitrydensity within the formed electronic circuit board.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide an electroniccircuit board and a method for producing an electronic circuit boardwhich overcomes some or all of the previously delineated drawbacks ofprior multi-layer electronic circuit boards and of prior electroniccircuit board forming methodologies and techniques.

It is a second object of the invention to provide a method for producinga multi-layer electronic circuit board which overcomes some or all ofthe previously delineated drawbacks of prior multi-layer electroniccircuit board forming methodologies and techniques, which allows for theformation or creation of an electronic circuit board which selectivelyreceives various electronic components, which allows for the selective,efficient, and reliable formation of metallized apertures, within theformed and/or created electronic circuit board, which cooperativelyallow for communication by and between these various electroniccomponents and which further cooperatively allow for the selectiveinterconnection of these contained components.

It is a third object of the invention to provide a method for producinga multi-layer electronic circuit board which overcomes some or all ofthe previously delineated drawbacks of prior multi-layer electroniccircuit board forming methodologies and techniques and which allows forthe selective formation of metallized apertures within a circuit board,which may be selectively connected or disconnected and/or selectivelyisolated from a formed electrical ground plane or bus.

It is a fourth object of the invention to provide a method for producinga multi-layer electronic circuit board which overcomes some or all ofthe previously delineated drawbacks of prior multi-layer electroniccircuit board forming methodologies and techniques and which allows forthe selective and efficient formation of air bridges and/or crossovercircuits and/or crossover members which are adapted to accommodate awide variety of component interconnections, assemblies, techniques,and/or methodologies.

According to a first aspect of the present invention, a method formaking an electric circuit board is provided. The method includes thesteps of providing a first member having a core which is containedbetween a first and a second layer of material; providing a secondmember having a core which is contained between a first and a secondlayer of material; providing a first and a second layer of a firstmaterial; providing a third member; removing a portion of the top andthe bottom layer of the first member, thereby exposing a first and asecond portion of the core of the first member; removing a portion ofthe top and bottom layer of the second member, thereby exposing a firstand a second portion of the core of the second member; creating a firstpre-circuit assembly by attaching the first layer of first material to afirst surface of the third member, attaching the second layer of firstmaterial to a second surface of the third member, attaching the firstmember to the first layer of first material, and attaching the secondmember to the second layer of first material; creating an aperturethrough the first pre-circuit assembly, thereby exposing a first surfaceof the first pre-circuit assembly within the aperture; applying anelectrically conductive material to the exposed first surface of thethird pre-circuit assembly; and selectively removing portions of thecore, thereby creating at least one air-bridge and forming an electricalcircuit assembly.

According to a second aspect of the present invention a circuit assemblyis provided. The circuit assembly is made by the process of forming afirst pre-circuit assembly having a first core member having a first anda second surface, a first plurality of electrically conductive membersdisposed upon the first surface, and a second plurality of electricallyconductive members disposed upon the second surface; forming a secondpre-circuit assembly having first and second circuit boards which areselectively attached to a dielectric adhesive material and whichcooperatively form a separation region; coupling the dielectric adhesivematerial to the second plurality of electrically conductive portions;removing certain portions of the first core member, thereby forming apedestal portion which abuts the separation region; extending theseparation through the pedestal portion, thereby forming a circuitboard.

According to a third aspect of the present invention, a circuit board isprovided and comprises a first electrically conductive member having afirst and a second surface; a first dielectric member which is coupledto the first surface; a second dielectric member which is coupled to thesecond surface; a first circuit assembly having a second electricallyconductive member which is coupled to the first dielectric member, thefirst circuit assembly further including a third electrically conductivemember and a first core member which is contained between the second andthe third electrically conductive members and which includes at leastone air-bridge; and a second circuit assembly having a fourthelectrically conductive member which is coupled to the second dielectricmember, the second circuit assembly further including a fifthelectrically conductive member and a second core member which iscontained between the fourth and the fifth electrically conductivemembers and which includes at least one air-bridge, the second circuitassembly cooperating with the first circuit assembly and with the firstand second dielectric material and with the first electricallyconductive member to form a multi-layer circuit board.

These and other objects, aspects, and advantages of the presentinvention will become apparent upon reading the following detaileddescription in combination with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1(a)-(m) are successive sectional side views of a multi-layercircuit board being produced and/or formed in accordance with theteachings of the preferred embodiment of the invention;

FIG. 2 is a top perspective fragmented view of the multi-layer circuitboard assembly shown in FIG. 1(1);

FIG. 3(a)-(f) are successive sectional side views of a multi-layercircuit board assembly being produced and/or formed in accordance withthe teaching of a second embodiment of the invention; and

FIG. 4(a)-(f) are successive sectional side views of a multi-layercircuit board assembly being produced and/or formed in accordance withthe teachings of a third embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Referring now to FIGS. 1(a)-(m), there is shown a process 10 for makingan electronic circuit board assembly in accordance with the teachings ofthe preferred embodiment of the invention. Particularly, process 10begins by obtaining and/or providing a member 12 having a first coreportion 14 which is operatively contained between a top and a bottomlayer or a top or first and a bottom or second member 16, 18, as bestshown in FIG. 1(a). It should be appreciated that the terms “first” and“second” should not be limited to the layers and/or members to whichthey specifically refer to within this specification (e.g., the term“first” may alternatively refer to bottom layer or member 18).

In one non-limiting embodiment of the invention, core portion or member14 comprises conventional and commercially available aluminum materialwhile layers/members 16, 18 comprise conventional, commerciallyavailable and substantially identical electrically conductive material,such as copper. As further shown best in FIG. 1(a), certain portions oflayers/members 16, 18 are removed by a conventional etching process inorder to create selectively formed apertures 20 within the layers 16,18, thereby creating exposed “areas” or surface portions 22, 24, 26, 28,30, 32, 34, 36, 38, and 40 of the core member 14. In one non-limitingembodiment of the invention, portions or pairs 22, 32; 24, 34; 26, 36;28, 38; and 30, 40 are respectively aligned (e.g., portions 32, 34, 36,38, 40 are respectively and wholly resident under portions 22, 24, 26,28, and 30, and portions 32, 34, 36, 38, and 40 are respectivelyidentical in size and shape to portions 22, 24, 26, 28, and 30). In afurther non-limiting embodiment of the invention, portions 22, 24, 26,28, 30, 32, 34, 36, 38, and 40 are each substantially similar in sizeand shape.

In one non-limiting embodiment of the invention, the thickness of thecore member 14 is about fifty to two hundred micrometers while thethickness of portions 16, 18 is substantially identical and is aboutfive to one hundred micrometers. Other sizes, shapes, thicknesses,and/or dimensions of members 14-18 may be utilized.

Process 10, as shown best in FIGS. 1(b) and 1(d), requires theacquisition and/or creation of substantially identical layers or members42, 44 each of which, in one non-limiting embodiment, comprisesubstantially identical and commercially available layers of dielectricadhesive material having a substantially identical size, shape, andthickness.

Process 10, as shown best in FIG. 1(c), further requires the acquisitionand/or creation of an electrically conductive member or layer 46 which,in one non-limiting embodiment, is formed from conventional andcommercially available electrically conductive material such as copperhaving a thickness, in one non-limiting embodiment, ranging from aboutfive micrometers to about one hundred fifty micrometers. Further, atleast one aperture or “hole” 48 is created within the member or layer 46by drilling, punching, and/or etching. As shown later, this at least oneaperture 48 will selectively form a “non-grounded” via or “throughhole”.

As shown best in FIG. 1(e), process 10 further requires the acquisitionand/or creation of a second member 50 which is substantially similar tomember 12. More particularly, member 50 includes a core portion ormember 52 which is substantially similar to core portion 14, and top orfirst and bottom or second members or layer portions 54, 56 which aresubstantially and respectively similar to member/layer portions 16, 18.Layers 54, 56 each have several selectively formed apertures 58 whichare effective to cause member 50 to have exposed top surface portions60, 62, 64, 66, 68 and exposed bottom surface portions 70, 72, 74, 76,78. In one embodiment of the invention, portions 60, 70; 62, 72; 64, 74;66, 76; and 68, 78 are aligned (e.g., portions 74, 72, 70, 76, and 78are respectively and wholly resident under portions 64, 62, 60, 66, and68 and portions 74, 72, 70, 76, and 78 are respectively identical insize and shape to portions 64, 62, 60, 66, and 68). In a furtherembodiment of the invention, portions 60, 62, 64, 66, 68, 70, 72, 74,76, 78 are each substantially similar in shape and size.

A pre-circuit assembly 92 is formed in the fifth step of the process 10,which is shown best in FIG. 1(f). Particularly, layer 18 of member 12 isattached by a conventional process or method to the top surface 80 ofmember or layer 42, effective to allow portions of layer 42 to overlaythe previously formed apertures 20 within the layer 18, and moreparticularly, to overlay the exposed portions 32, 34, 36, 38, 40. Thebottom surface 82 of member or layer 42 is attached, by a conventionalprocess or method, to the top surface 84 of layer or member 46, therebyoverlaying the previously formed aperture 48 and causing a portion ofthe member 42 to fill the aperture 48. The bottom surface 86 of themember 46 is attached, by a conventional process or method, to the topsurface 88 of the layer or member 44 and the attached surface 88overlays the previously formed aperture 48. Further, the bottom surface90 of the layer 44 is attached, in a conventional manner, to the toplayer 54 of member 50, effective to overlay apertures 58 within layer 54and to, more particularly, overlay exposed portions 60, 62, 64, 66, and68. This formed pre-circuit assembly 92 is best shown in FIG. 1(f).

As best shown in FIG. 1(g), process 10 continues with the creation of apre-circuit assembly 94 which is created by selectively forming firstand second apertures 96, 98 within the formed pre-circuit assembly 92.These apertures 96, 98 may be formed by drilling, etching, punching, orby any other conventional process or methodology. Particularly, thefirst aperture 96 is aligned with (e.g., extends through) the previouslycreated aperture 48 and effectively extends the previously createdaperture 48 through the formed pre-circuit assembly 94. The secondaperture 98, in one non-limiting embodiment, is substantially identicalin shape and size to the aperture 96 and is aligned with (e.g., extendsthrough) apertures 30, 40. It should be realized that apertures 96, 98may be of various sizes and shapes and that nothing in this descriptionshould or is meant to limit these apertures 96, 98 to any certain sizeor shape.

Exposed surfaces 100, 102 of pre-circuit assembly 94 are respectivelycontained within and/or reside within and/or define the apertures 96, 98and form respective “interior surfaces” of apertures 96, 98. In onenon-limiting embodiment of the invention, member 46 functions as orcomprises an electrical ground plane (i.e., member 46 is physically andelectrically coupled to a source of electrical ground potential). Asshown, member 46 does not reside within aperture 96 and does not resideupon surface 100. Hence, interior surface 100 is electrically isolatedand/or electrically disconnected from member 46, thereby causingaperture 96 to be a “non-grounded via” or a “non-grounded aperture”.Member 46 does reside within aperture 98 and does reside upon surface102. Hence, interior surface 102 is electrically connected to member 46,thereby causing aperture 98 to be a “grounded via” or a “groundedaperture”.

In the eighth step of process 10, which is shown best in FIG. 1(h), acertain substance or material 104 is applied upon exposed portions 106of layers 14, 42, 44, 52 which reside within apertures 96, 98 and whichreside upon and/or which form an integral part of surfaces 100, 102,thereby forming pre-circuit assembly 108, having a top surface 110 and abottom surface 112.

In one non-limiting embodiment of the invention, the dielectric adhesivematerial layers or members 42, 44, 52, and 14 which are contained withinportion 106 are “metallized” by using known “direct metallization”methods or by use of conventional electroless methods and/or by use ofan electrically conductive layer 104 which is formed upon the adhesivesurface 106. The applied material 104 may, in one non-limitingembodiment, comprise palladium alloy, carbon, graphite, or copper or anyother suitable and/or similar material. It should be appreciated thatmaterial 104 is applied to these dielectric adhesive members or layers14, 42, 44, 52 to “metallize” the exposed portions 106. Material 104 issimilarly bonded to these respective portions of conductive members 16,18, 46, 54, and 56 which reside within the apertures 96, 98, therebyallowing for the creation of a continuous electrically conductive layerover aperture boundary or defining surfaces 100, 102.

In the ninth step of process 10, which is best shown in FIGS. 1(i), aconventional and commercially available “resist” material 114 is appliedand/or “screen printed” in a conventional and known manner upon most ofthe exposed portions of layer 16 and layer 14 and upon most of thelayers 52 and 56, effective to cause certain portions 116 of layer 16and certain portions 118 of layer 56 to remain exposed, and to form apre-circuit assembly 120. Particularly, in one non-limiting embodiment,these certain portions of layers 116, 118 are proximate to therespective and previously formed apertures 96, 98.

In the tenth step of process 10, which is best shown in FIG. 1(j), aconventional and commercially available copper material 122 is applied(e.g., electroplated) upon the certain exposed portions 116, 118 andalso, in one non-limiting embodiment, upon the material 104 covering thefirst and second surfaces 100, 102, thereby forming a pre-circuitassembly 124.

In the eleventh step of process 10, which is shown best in FIG. 1(k),material 114 is removed by a conventional process or methodology,thereby forming a pre-circuit assembly 126. In the twelfth step ofprocess 10, as best shown in FIG. 1(l) and FIG. 2, the members 14, 52are selectively etched in order to selectively form air-bridges orcrossover members 128, thereby creating a multi-layer circuit assembly130. The formed air-bridge or crossover members 128, in one non-limitingembodiment, cooperatively form a void 132.

In the twelfth step of process 10, which is shown best in FIGS. 1(m), aconventional and commercially available polymer material 134 is appliedto pre-circuit assembly 130 to substantially “fill” the void 132,thereby “underfilling” and structurally supporting the formed airbridges or crossover members 128 and creating a pre-circuit assembly136.

It should be appreciated that the selective etching of core members 14,52 allows the air bridges and/or crossover members 128 to be efficientlyand relatively easily formed in a cost effective manner. Further, suchetching allows for the selective formation of air bridges and/orcrossover members 128 which may have a selected shape and/or size,thereby allowing the selectively and etchably created air bridges and/orcrossover members 128 to support a wide variety of circuits andcomponents, effective to selectively and efficiently accommodate a widevariety of circuit interconnection methodologies and/or techniques.Further, the structural support given to the formed air bridges orcrossover members 128 allows the air-bridges or crossover members 128 tosupport relatively heaving wiring and/or components, thereby increasingthe overall utility of the formed circuit assembly 136.

It should further be appreciated that the apertures 96, 98 may also beefficiently formed and/or created in a “single step” operation whichobviates the need to separately drill or create apertures in eachmember/component which selectively forms the created multi-layer circuitassembly 136, thereby increasing the overall efficiency of process 10.

Referring now to FIGS. 3(a)-(f), there is shown a process 140 for makingan electronic circuit board assembly in accordance with the teachings ofan alternate embodiment of the invention. Particularly, process 140begins by obtaining and/or providing a pre-circuit assembly 142 having acore portion or member 144. As shown, several electrically conductiveportions or members 146 are contained and/or disposed upon the top orfirst surface 147 of member 144, and several electrically conductiveportions or members 148 are contained and/or disposed upon the bottom orsecond surface 149 of member 144, as shown best in FIG. 3(a). In onenon-limiting embodiment of the invention, core portion 144 comprisesconventional and commercially available aluminum material whilelayers/members 146, 148 comprise conventional, commercially available,and substantially identical electrically conductive material, such ascopper. Hence, member 142 comprises, in one non-limiting embodiment, a“copper clad aluminum member”.

In the second step of process 140, as shown best in FIG. 3(b), a layerof adhesive material 150 is acquired and/or created having a top orfirst surface 152 and a bottom or second surface 154. Virtually any typeof adhesive material may be selectively utilized within this process140.

In the third step of process 140, as shown best in FIG. 3(c), apre-circuit assembly 156 is provided. Particularly, in one non-limitingembodiment, pre-circuit assembly 156 is comprised of or includes a coreportion 158 which contains apertures 160, 162, 164. Particularly, coreportion 158 contains a first electrically conductive layer or member 166which is disposed on top or first surface 167 and a second electricallyconductive layer or member 168 which is disposed on bottom or secondsurface 169. As shown, members 166, 168 each include apertures which arealigned with a unique one of the respective apertures 160, 162, and 164.In one non-limiting embodiment of the invention, core portion 158comprises conventional and commercially available laminate materialwhile layers/members 166, 168 comprise conventional, commerciallyavailable, and substantially identical electrically conductive material,such as copper.

In another non-limiting embodiment of the invention, core portion 158may be formed from a wide variety of conventional and commerciallyavailable individual circuit boards 159(a)-159(d) such as a conventional“FR-4” or a conventional “rigid circuit board”. As shown,boards/portions 159(a) and 159(b) are separated by a separationdistance, region, or aperture 164; portions 159(c) and 159(b) areseparated by a separation distance, region, or aperture 162; andportions 159(b) and 159(a) are separated by a separation distance,region, or aperture 160. It should be appreciated that selective numbersof “pre-formed” and commercially available boards 159(a-d) may beutilized within assembly 140.

In the fourth step of process 140, as shown best in FIG. 3(d), portions148 of pre-circuit assembly 142 are attached to the top surface 152 ofmaterial 150. Material 166 of pre-circuit assembly 156 is attached tothe bottom surface 154 of material 150, thereby forming pre-circuitassembly 170. It should be realized that circuit assembly 156 may beformed/created concurrently with assembly 140, or separately. Moreover,the use of commercially available circuit assemblies 159(a)-159(d)reduces the overall cost of process 140 and allows for the use of thecreated circuit assemblies in a wide variety of applications. Moreover,separate fabrication and/or creation of assemblies 142 and 156 allowsfor the separate creation of power traces and allows for a moreefficient creation of the final circuit board assembly.

In the fifth step of process 140, as best shown in FIG. 3(e), process140 continues by applying a certain etchant material (e.g., an aluminumetchant material) to certain selective portions of core portion 144,effective to remove or “etch away” certain selective portions of coreportion 144, thereby forming pillar portions 172(a)-(e) of core portion144 which reside upon the top surface 152 of material 150 and which mayselectively overlay apertures 160, 162, 164, thereby forming pre-circuitassembly 174.

In the sixth step of process 140, as shown best in FIG. 3(f), process140 continues by drilling or otherwise causing apertures 160, 162, 164to extend through pre-circuit assembly 174 and through pillars 172(a),172(c), 172(e), thereby forming pre-circuit assembly 176. It should beappreciated that apertures 160, 162, 164 may be electroplated orprocessed in a manner which allows for apertures 160, 162, 164 to formcircuit interconnections.

Referring now to FIGS. 4(a)-(e), there is shown a process 180 for makingan electronic circuit board assembly in accordance with the teachings ofan alternate embodiment of the invention. Particularly, process 180begins by obtaining and/or providing a pre-circuit assembly or a member182 having a core portion 184 which includes electrically conductiveportions or members 186 which are disposed upon top or first surface187, and several electrically conductive portions or members 188 whichare disposed upon bottom or second surface 189. In one non-limitingembodiment of the invention, core portion 184 comprises conventional andcommercially available aluminum material while layers/members 186, 188comprise conventional, commercially available, and substantiallyidentical electrically conductive material, such as copper.

In the second step of process 180, as shown best in FIG. 4(b) and FIG.4(d), a pair of dielectric adhesive layers or members 190 and 192 areacquired and/or created. These members 190, 192 respectively have topsurfaces 194, 196 and bottom surfaces 198, 200.

In the third step of process 180, as shown best in FIG. 4(c), apre-circuit assembly 202 is provided which is generally and relativelyflexible. Particularly, assembly 202 comprises a substantially andrelatively flexible core member or portion 204 having severalelectrically conductive portions or members 206 which are disposed uponthe top or first surface 207 and having several electrically conductiveportions or members 208 which are selectively disposed upon the secondor bottom surface 209.

In the fourth step of process 180, as shown best in FIG. 4(e),pre-circuit assembly 210 is provided. Particularly, pre-circuit assembly210 includes a core member or portion 212 having several electricallyconductive portions or members 214 disposed upon a first or top surface215 and having several electrically conductive portions or members 216selectively disposed upon a second or bottom surface 217. In onenon-limiting embodiment of the invention, core portion 212 comprisesconventional and commercially available aluminum material whilelayers/members 214, 216 each comprise conventional, commerciallyavailable, and substantially identical electrically conductive material,such as copper.

In the fifth step of process 180, as shown best in FIG. 4(f), members188 of pre-circuit assembly 182 are operatively attached or coupled tothe top surface 194 of adhesive 190. Portions 206 of pre-circuitassembly 202 are then operatively connected and/or coupled to the bottomsurface 198 of material 190. Portions 208 of pre-circuit assembly 202are coupled to the top surface 196 of material layer 192. Portions 214of pre-circuit assembly 210 is operatively connected and/or coupled tothe bottom surface 200 of material layer 192, forming a pre-circuitassembly 270 which may be processed by drilling, electroplating, and/orany other process or methodology producing circuit layerinterconnections. It should be appreciated that pre-circuit 270 may besubjected to a certain etchant material (e.g., and aluminum etchantmaterial) which “etches away” or removes certain portions of core metalmembers 184, 212 and which allows the formed pre-circuit assembly to besubstantially and relatively flexible.

It should be appreciated that the pre-circuit assemblies formed byprocesses 140, 180 may be constructed and/or otherwise assembled by theuse of multi-layer circuit boards which are formed prior to the use ofprocesses 140, 180 or by attaching multi-layer circuit boards formedconcomitantly with process 140, 180. It should further be appreciatedthat “adhesive” or “non-adhesive” containing circuit boards and/orcircuit board assemblies may be alternately and selectively usedconcomitantly with processes 140, 180. In one non-limiting embodiment ofthe invention, these circuit boards may be alternately and selectivelyused to produce circuit interconnections of the “power” type, the“signal” type, the “ground plane” type, or the “interconnection” type.

It should be understood that the invention is not limited to the exactembodiment or construction which has been illustrated and described butthat various changes may be made without departing from the spirit andthe scope of the invention.

What is claimed is:
 1. A circuit board comprising: a first electrically conductive member having a first and a second surface; a first dielectric member which is coupled to said first surface; a second dielectric member which is coupled to said second surface; a first circuit assembly having a second electrically conductive member which is coupled to said first dielectric member, said first circuit assembly further including a third electrically conductive member and a first core member which is contained between said second and said third electrically conductive members and which includes at least one air-bridge; and a second circuit assembly having a fourth electrically conductive member which is coupled to said second dielectric member, said second circuit assembly further including a fifth electrically conductive member and a second core member which is contained between said fourth and said fifth electrically conductive members and which includes at least one air-bridge, said second circuit assembly cooperating with said first circuit assembly and with said first and second dielectric material and with said first electrically conductive member to form a multi-layer circuit board.
 2. The circuit board of claim 1 further comprising material which supports said at least one air-bridge of said first circuit assembly.
 3. The circuit board of claim 1 wherein said first and second core members comprise aluminum and wherein said first electrically conductive member comprises copper.
 4. The circuit board of claim 1 further comprising a first aperture having a first surface which extends through said first, second, third, fourth, and fifth electrically conductive members, said first and second dielectric members, and said first and second core members.
 5. The electronic circuit board of claim 4 further comprising a second aperture which has a second surface which is electrically isolated from said first electrically conductive member.
 6. The circuit board of claim 5 wherein said first electrically conductive member is coupled to an electrical ground potential.
 7. The circuit board of claim 5 wherein said first and second apertures contain electroplated material upon said respective first and second surfaces.
 8. A method for making an electrical circuit assembly comprising the steps of: providing a first member having a first core portion which is contained between a top and a bottom layer; providing a second member having a second core portion which is contained between a top and a bottom layer; providing first layer and a second layer of a first material; providing a third member; removing a portion of said top and said bottom layer of said first member, thereby exposing at least two portions of said core portion of said first member; removing a portion of said top and said bottom layer of said second member, thereby exposing at least two portions of said core portion of said second member; creating a first pre-circuit assembly by attaching the first layer of said first material to a first surface of said third member, attaching the second layer of said first material to a second surface of said third member, attaching said first member to said first layer of said first material, and attaching said second member to said second layer of said first material; creating an aperture through said first pre-circuit assembly, thereby causing a portion of said first pre-circuit assembly to be contained within said created aperture; applying an electrically conductive material to said portion of said first pre-circuit assembly which is contained within said aperture; and selectively removing portions of said first and second core portions, thereby creating a circuit assembly having at least one air-bridge and forming an electrical circuit assembly.
 9. The method of claim 8 wherein said third member comprises an electrical ground plane and wherein said method further comprises the step of isolating said portion of said first pre-circuit assembly which is contained within said aperture from said third member.
 10. The method of claim 9 further comprising the steps of creating a second aperture through said first pre-circuit assembly, thereby exposing a second surface of said first pre-circuit assembly within said second aperture, said second surface including a portion of said third member.
 11. The method of claim 9 wherein said step of applying an electrically conductive material to said portion of said first pre-circuit assembly comprises the step of electroplating copper material upon said portion of said first pre-circuit assembly.
 12. The method of claim 8 wherein said first material comprises a dielectric adhesive material.
 13. The method of claim 8 wherein said core portion of said first member comprises aluminum and wherein said top and bottom layers each comprise copper.
 14. The method of claim 8 further comprising the step of creating a first aperture within a certain portion of said third member; and extending said first aperture through said first pre-circuit assembly.
 15. The method of claim 8 further comprising the step of applying said electrically conductive material to certain portions of said top layer of said first member and said bottom layer of said second member.
 16. The method of claim 8 wherein said step of selectively removing portions of said core portion comprises the step of selectively etching said core.
 17. A method for making a circuit board comprising the steps of: forming a first pre-circuit assembly having a first core member having a first and a second surface, said first pre-circuit assembly further including a first plurality of electrically conductive members disposed upon said first surface and a second plurality of electrically conductive members disposed upon said second surface; forming a second pre-circuit assembly having first and second circuit boards which are selectively attached to a dielectric adhesive material and which cooperatively form a separation region; coupling said dielectric adhesive material to said second plurality of electrically conductive portions; removing certain portions of said first core member, thereby forming at least one pedestal portion which abuts one of said separation regions; and extending said separation region through said at least one pedestal portion, thereby forming a circuit board.
 18. The method of claim 17 wherein said core member comprises aluminum.
 19. The method of claim 18 wherein said first and second plurality of electrically conductive members each comprise copper.
 20. The method of claim 19 wherein said step of removing said certain portions of said first core member comprises selectively etching said first core member. 